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冰川冻土 ›› 2015, Vol. 37 ›› Issue (1): 249-257.doi: 10.7522/j.issn.1000-0240.2015.0028

• 寒旱区水文与水资源 • 上一篇    下一篇

季风区长沙站大气水汽和降水中δ18O的模拟

章新平1, 关华德1,2, 张新主1, 吴华武1, 李广1, 黄一民1   

  1. 1. 湖南师范大学 资源与环境科学学院, 湖南 长沙 410081;
    2. School of the Environment, Flinders University, Adelaide 5001, Australia
  • 收稿日期:2014-07-09 修回日期:2014-11-25 出版日期:2015-02-25 发布日期:2015-03-23
  • 作者简介:章新平(1956-),男,湖南长沙人,教授,1993年在中国科学院兰州冰川冻土研究所获博士学位,现主要从事气候变化的研究.E-mail:zxp@hunnu.edu.cn.
  • 基金资助:

    国家自然科学基金项目(41171035; 41271095); 湖南省重点学科建设项目(2011001); 湖南省"百人计划"项目(2010004)资助

Simulation of δ18O in atmospheric vapour and precipitation in Changsha Station, East Asian monsoon regions

ZHANG Xinping1, GUAN Huade1,2, ZHANG Xinzhu1, WU Huawu1, LI Guang1, HUANG Yimin1   

  1. 1. College of Resources and Environmental Sciences, Hunan Normal University, Changsha 410081, China;
    2. School of the Environment, Flinders University, Adelaide 5001, Australia
  • Received:2014-07-09 Revised:2014-11-25 Online:2015-02-25 Published:2015-03-23

摘要:

利用稳定同位素大气水平衡模式(iAWBM)模拟了季风区长沙站大气水汽和降水中δ18O的时间变化, 并与实际监测结果进行比较, 其目的在于检验iAWBM在模拟季风区大气中水稳定同位素循环方面的能力, 揭示影响水稳定同位素变化的主要原因, 改善对季风区水循环中稳定同位素效应的理解和认识. 模拟结果很好地再现了长沙降水中δ18O的季节变化, 季风区降水中稳定同位素雨季被贫化旱季被富集的基本特点以及存在的显著降水量效应均被模拟出. 在2010年1月-2012年12月, 模拟的冬季风盛行期间的加权平均δ18O为-6.58‰, 与该时段的实际监测值相当; 模拟的夏季风盛行期间的加权平均δ18O为-9.58‰, 低于该时段的实际监测值. iAWBM主要利用大气的可降水量、水汽通量、蒸发量和降水量4个驱动变量来模拟水稳定同位素的循环. 其中, 可降水量对水稳定同位素变化的贡献被包含在其他3个驱动变量中. 水汽通量对水汽同位素变化的贡献具有富集和贫化的双重作用, 蒸发量和降水量对水汽同位素变化的贡献分别具有富集和贫化的作用. 在对水汽同位素起富集作用的两个因子中, 水汽通量的平均同位素贡献为1.66‰, 贡献率为63.97%; 蒸发量的平均同位素贡献为0.91‰, 贡献率为36.03%, 水汽通量的同位素贡献起主要作用. 在对水汽同位素起贫化作用的两个因子中, 水汽通量的平均同位素贡献为-1.40‰, 贡献率为53.47%; 降水量的平均同位素贡献为-1.09‰, 贡献率为46.53%, 水汽通量和降水量的同位素贡献大致相当.

关键词: 季风区, 稳定同位素, iAWBM, 模拟, 分馏

Abstract:

Using the isotope enabled atmospheric water balance model (iAWBM), the temporal variations of δ18O in atmospheric vapor and in precipitation are simulated and compared with actual observed data at Changsha station located in East Asian monsoon regions, in order to examine the capability of iAWBM simulating the water isotope cycle in atmosphere in monsoon regions, to deal with the main causes of isotope effects and to improve the understanding of isotope effects in the water cycle in monsoon regions. The simulated results reproduce well the observed seasonal variations of δ18O in precipitation. The basic characteristics that the stable isotopes in precipitation are depleted during the rainy season and enriched during the drought season, and the observed amount effect are well simulated under daily time scale. The simulated weighted average -6.58‰, of δ18O in precipitation during prevailing winter monsoon, is almost the same as actual one in the same period, but the value -9.58‰ during prevailing summer monsoon is lower than the actual one in the same period, from January, 2010 to December, 2012. As the designed, four forcing variables, atmospheric precipitable water, vapor flux, evaporation and precipitation, are combined into iAWBM for simulating the stable water isotope cycle. Of these four variables, the impact of precipitable water on the variation of stable water isotopes is embodied in the other three variables. Vapor flux has dual roles of enriching and depleting stable isotopes in vapor. Evaporation and precipitation have the role of enriching and depleting stable isotopes in vapor, respectively. For two variables that have the enriching impact on stable isotopes in vapor, the average isotopic contribution amount from vapor flux is 1.66‰ with the average contribution rate of 63.97%, and that from evaporation is 0.91‰ with the average contribution rate of 36.03%, showing that the isotopic contribution of vapor flux plays a major role. For two variables that have the depleting impact on stable isotopes in vapor, the average isotopic contribution amount from vapor flux is -1.40‰ with the average contribution rate of 53.47%, and that from precipitation is -1.09‰ with the average contribution rate of 46.53%, showing that the isotopic contribution of vapor flux is comparable to that of precipitation.

Key words: monsoon regions, stable isotope, iAWBM, simulation, fractionation

中图分类号: 

  • P426.61+2